function list high_freq_list (const matrix x, int compfac, string vname)
  list ret = deflist()
  scalar T = $nobs
  if rows(x) != compfac*T || cols(x) != 1
     funcerr "Invalid x matrix"
  endif
  matrix m = mreverse(mshape(x, compfac, T))'
  loop i=1..compfac
    scalar k = compfac + 1 - i
    ret += genseries(sprintf("%s%d", vname, k), m[,i])
  endloop
  setinfo ret --midas 
  return ret
end function

# construct a little "quarterly" dataset
nulldata 12
setobs 4 1980:1

# generate "monthly" data, 1,2,...,36
matrix x = seq(1,3*$nobs)'
print x
# turn into midas list
list H = high_freq_list(x, 3, "test_m")
print H --byobs